Correlation between compressive strength of concrete and ultrasonic pulse velocity: A case of study and a new correlation method

• Published in: Construction & building materials 2023-03, Vol.369, p.130569, Article 130569
• Main Authors: Mata, Ramón, Ruiz, Rafael O., Nuñez, Eduardo
• Format: Article
• Language: English
• Subjects: Assessment of existing structures; Concrete core; Concrete strength; Destructive testing; In-situ concrete strength evaluation; UPV test
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2023.130569

•The proposed method assumes the compressive concrete strength and the UPV as a multivariate Gaussian PDF which is calibrated using the results coming from destructive tests.•The most important feature of the proposed method is that the practitioner can incorporate the dispersion of the in situ UPVs in terms of percentiles while the inference of the compressive concrete strength is offered based on a probability of exceedance or a particular confidence interval.•The proposed method requires the selection of the percentile associated with the UPV and the probability of exceeding given Vo.•This formulation facilitates the generation of maps where f́c depends on the in situ UPV percentile and the probability of exceedance for the concrete strength. Concrete strength assessment is an important topic in evaluating existing structures. Formerly, only destructive tests were employed, limiting the number of tests due to their complexity and cost. Nowadays, the application of non-destructive tests has been booming to determine material strength, offering a more accessible and cheaper strategy than its counterpart. Non-destructive strategies are based on two steps: (1) the identification of the correlation between the concrete strength and another parameter that is easy to measure in situ, and (2) the use of this easy-to-measure parameter to infer the concrete strength in any desired element of the structure. The most common parameter adopted for this purpose is the Ultrasonic Pulse Velocity (UPV). However, the correlation between concrete strength and UPV must be determined via destructive experiments. From the research perspective, attention has focused on determining the correlation coefficient and the range of credibility for estimating the inferred concrete strength. Despite it, this strategy has remained elusive in the fundamental understanding and accounting of the joint dispersion of the concrete strength and the UPV. The present work addresses this knowledge gap by proposing a new correlation method based on probability interpretations to infer the compressive concrete strength from in-situ UPV measurements and including the dispersion evidenced in UPV measurements in both steps mentioned. The results demonstrated that it is possible to determine the confidence interval for the concrete compressive strength given a certain percentile of the UPV measured in situ. Finally, the application of the proposed method is illustrated through a case study, which is re